Research by Acemoglu and Linn, which examined pharmaceutical drug development, found that:

a$.$

respondents would rather have a disease that afflicts a small number of people than a common one.

b$.$

the larger the potential market, the likelier drug companies are to develop a drug for that market.

c$.$

profits are not an important consideration for which drugs are developed.

d$.$

pharmaceutical companies earn normal rates of return in the long run, despite considerable market power in the short run.